Platform and method for identifying past exposure to chemical agents or heavy metals

ABSTRACT

A method for determining past exposure to chemical agents or heavy metals may include coating a capture material with a capture reagent. The capture reagent may be selected based on an ability of the capture reagent to bind with a target antibody, and the target antibody may be an indicator associated with a particular chemical agent or heavy metal. The method may further include interrogating a clinical sample associated with an individual by forming a mixture of the capture material and the clinical sample, and determining an exposure status of the individual to the particular chemical agent or heavy metal based on whether the capture material demonstrates capture of the indicator.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/249,842, filed on Aug. 29, 2016, which claims the benefit of U.S.Provisional Application No. 62/212,617, filed on Sep. 1, 2015; theentire contents of both are incorporated herein by reference.

STATEMENT OF GOVERNMENTAL INTEREST

This invention was made with Government support under contract number2012-12050800010 awarded by the Intelligence Advanced Research ProjectsActivity (IARPA). The Government has certain rights in the invention.

TECHNICAL FIELD

Example embodiments generally relate to technology for detecting pastexposure to chemical agents or heavy metals, and more particularlyrelates to an immunoassay platform and method for the same.

BACKGROUND

Methods have been developed to determine the presence of biomarkers thatprovide evidence of prior exposure to biological agents. However, forchemical agent exposure, particularly when small levels of exposureoccurred or exposure occurred some time ago, there has not typicallybeen any way to determine what exposures have occurred. Furthermore,even for more recent or large level exposures, since chemical agents orheavy metals (ex. Pb) are often too small to be immunogenic, the agentswill flush out of an individual's system in a relatively short time andessentially leave no trace to be measured in relatively short period oftime. Thus, for example, exposure events are often diagnosed after thefact based on the symptoms experienced by the individual or other publichealth information, and not based on any positive identification ofspecific agents/biomarkers found in the individual's system.

More recently, the idea has developed that there may be some way todetect past exposures to chemical agents, or even heavy metals. Recentword events related to intelligence community needs and general publicsafety concerns have driven continued pursuit of a solution forproviding this ability. Accordingly, it may be desirable to develop amethod for detecting such past exposures, and perhaps also capable ofscanning for multiple different exposures in a single test.

Biomarkers unique to specific agents, chemical or heavy metals thatcould cause harmful effect on human health are useful for in diagnosticscenarios. Determination of an individual immunomics status by assessingthe level of specific immune responses associated with exposures with anarray of chemical compounds and their metabolites would significantlyenhance our capability to intervene and track deliberate or accidentalincidences to chemical agents of interest. Furthermore, subsequentidentification of specific modified host peptide sequences that bind tocirculating antibodies (Abs) could provide insights into autoimmunediseases and environmental exposures. However, there is an unmettechnological gap for specifically determining acute, past and chronicexposures to small chemicals and heavy metals, limiting our ability topinpoint the mechanism by which these chemicals affect the overallhealth of the host. Published data suggest that many chemicalscovalently attach to host proteins and become haptenized, thereforestimulating the immune system. In addition, a published report indicatesthat mice exposed to lead produce a specific immune response against 2altered neural proteins. Generating in vitro all possible adducts withhost proteome that could form as a result of chemical exposure event orall possible altered host protein that could result by exposure to heavymetals would greatly enhance our capability to identify host immuneresponse biomarkers in clinical serum samples. The subsequent Absdirected against these chemical adducts and/or altered host proteins viaimmunoassay techniques would pinpoint the specific peptide adducts oraltered peptides that become haptenized.

BRIEF SUMMARY OF SOME EXAMPLES

Accordingly, some example embodiments may enable the provision of asolution for addressing the issues described above. In this regard, forexample, some embodiments may enable the provision of a screeningplatform capable of determining past exposure to one or a plurality ofdifferent chemicals, or heavy metals.

In one example embodiment, a method for determining past exposure tochemical agents or heavy metals is provided. The method may includecoating a capture material with a capture reagent. The capture reagentmay be selected based on an ability of the capture reagent to bind witha target antibody, and the target antibody may be an indicatorassociated with a particular chemical agent or heavy metal. The methodmay further include interrogating a clinical sample associated with anindividual by forming a mixture of the capture material and the clinicalsample, and determining an exposure status of the individual to theparticular chemical agent or heavy metal based on whether the capturematerial demonstrates capture of the indicator.

In another example embodiment, an apparatus for determining pastexposure to chemical agents or heavy metals is provided. The apparatusmay include a capture material and a test volume. The capture materialmay be coated with a capture reagent. The capture reagent may beselected based on an ability of the capture reagent to bind with atarget antibody. The target antibody may be an indicator associated witha particular chemical agent or heavy metal. The test volume may be avolume in which the capture material is provided for mixture with aclinical sample associated with an individual to interrogate theclinical sample. The apparatus may be configured to provide an outputfor determining an exposure status of the individual to the particularchemical agent or heavy metal based on whether the capture materialdemonstrates capture of the indicator.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described example embodiments of the invention in generalterms, reference will now be made to the accompanying drawings, whichare not necessarily drawn to scale, and wherein:

FIG. 1 illustrates a flow diagram to illustrate the operationsassociated with chemical agent exposure detection in accordance with anexample embodiment according to an example embodiment;

FIG. 2 illustrates a block diagram showing operations an apparatus forperforming exposure detection relative to chemical agents and/or heavymetals according to an example embodiment;

FIG. 3 illustrates a block diagram showing operations associated with amethod of detecting exposure events according to an example embodiment;and

FIG. 4 illustrates a block diagram showing operations associated with amethod for identifying possible host biomolecule modifications thatillicit immune response following an exposure event to a chemical agentor heavy metal.

DETAILED DESCRIPTION

Some example embodiments now will be described more fully hereinafterwith reference to the accompanying drawings, in which some, but not allexample embodiments are shown. Indeed, the examples described andpictured herein should not be construed as being limiting as to thescope, applicability or configuration of the present disclosure. Rather,these example embodiments are provided so that this disclosure willsatisfy applicable legal requirements. Like reference numerals refer tolike elements throughout.

As indicated above, some embodiments of the present invention may relateto providing an exposure screening platform for detecting past chemicalor heavy metal (e.g., lead) exposure. Some example embodiments mayfurther allow for multiplexing relative to the screening operation sothat the possibility to screen for multiple chemicals or heavy metals isprovided. Some examples may employ a chemical-phage library,chemical-DNA library and/or protein modification library for chemicalsand heavy metals of interest to enable the capture of antibodiesdirected at the chemical motifs or modifications. Example embodimentsmay also be rapidly deployable to respond to public health orintelligence-related incidents to confirm whether exposures haveoccurred, or may be employed as part of a routine health monitoringprogram which could develop a timeline for a particular patient or setof patients to determine when exposures may have occurred.

Example embodiments attempt to solve the problem of determining whetheran individual has experienced a past exposure to a heavy metal such aslead, or to a chemical agent such as sarin gas, mustard gas, etc. Asdiscussed above, some chemical agents tend to be flushed from the bodyrelatively quickly (e.g., within days) after exposure. Thus,confirmation of exposure can be difficult if testing is not immediatelyperformable. However, some chemical agents may react with variousproteins to form protein adducts in blood plasma. The formation of theseprotein adducts acts somewhat like an immune response, which can act asmemory of the exposure event. This memory, as detectable through theexistence of protein adducts, can indicate the existence of the exposureevent.

Exposure to heavy metals such as lead may also be detected through asomewhat similar memory process for recording the exposure event. Morespecifically, although exposure to lead does not form protein adducts inthe manner described above, the exposure does modify (i.e., causestructural changes to) biomolecules. The modification that occurs whenbiomolecules bind with metal ions may generate haptens that induce animmune response. Antibodies against the modification may therefore bedetected in an individual as evidence or memory indicative of theexposure event.

In both of the example cases described above (i.e., chemical agent andheavy metal exposure cases), it may be possible to generate a library ofindicators that can be searched for to provide evidence of exposure. Forexample, in some cases, a phage or yeast library that display humanpeptidome may be provided to generate all possible adducts ormodification with minimal bias. The library will be exposed to thechemical or heavy metal to generate all possible modification that wouldbe expected during actual exposure. The library may define a uniqueidentifier sequence tag for each of a plurality of chemicals. When agiven peptide is detected, an indication may be provided that a covalentchemical linkage was formed based on exposure to a chemical identifiedfrom the phage library. Alternatively or additionally, a DNA library maybe provided to identify indicators. For example, a DNA library withunique sequences with primary amine or sulfhydryl moiety at the 5′-endmay be provided. For heavy metal exposure detection, a library ofmodifications that could possibly occur in vivo may be provided.

In an example embodiment, the indicators from the library (e.g., the DNAlibrary, the phage-library, or the modification library) may be used tointerrogate clinical samples (e.g., of blood, sera, or other suitablebodily fluids) to determine if any antibody against a particularmodification or protein adducts can be found. If any unique antibody isfound that binds only to a particular entry in the library (e.g., aparticular modified biomolecules, a particular protein adduct, etc.),then the corresponding implication is that the sample was derived froman individual that has been exposed to the metal ion or chemical agentassociated with the indicator that was detected.

FIG. 1 illustrates a flow diagram to illustrate the operationsassociated with chemical agent exposure detection in accordance with anexample embodiment. In this regard, as shown in FIG. 1, a clinicalsample 100 (e.g., blood, sera, or other bodily fluid) may be providedfrom an individual whose potential exposure to selected chemical agentsis to be tested. Using the aforementioned phage/yeast library adductreagents, all host peptide adducts to each chemical of interest oraltered host biomolecule that correspond to each heavy metal that becomehaptenized to illicit immune response could be identified. Based on thisinformation, a peptide-adduct array sensor will be developed and will becoated as capture molecules. A plurality of reagents corresponding tochemical agents (i.e., capable of binding with antibodies generated bysuch chemical agents) may be defined in respective ones of aphage-linked chemical library 110 or a DNA-linked chemical library 120.The reagents may correspond to chemicals of interest for testingpurposes. Based on the known antibodies that would be generatedresponsive to exposure to various chemicals (as further provided byinformation that may be in the libraries), capture beads or some othercapturing reagent 130 may be provided to bind to antibodies (if any) inthe clinical sample 100. This process may correspond to the captureblock 140 of FIG. 1.

After the clinical sample 100 is exposed to the capturing reagent 130, adetermination may be made as to whether antibodies were captured,thereby indicating that the individual has been exposed to thecorresponding chemical agent. In the case of the DNA-linked library,polymerase chain reaction (PCR) may be used to facilitate enhancingdiagnostic sensitivity by coupling antibody detection with DNA tags thatcan be exponentially amplified. As such, in this example, the PCR block150 corresponds to an amplification or sensitivity enhancement step. Areal-time PCR curve 160 may be generated to show the results of theamplification operations.

Given that multiple capturing reagents may be defined for multiplecorresponding chemicals to permit multiplexing relative to the sensorplatforms exposure detection capabilities, a microarray probe captureoperation 170 may be employed to display the results in a multiplexdetection format 180. The multiplex detection format 170 may illustrateresults for each of a plurality of detection cells that are generatedbased on corresponding different capturing reagents that are exposed tothe clinical sample 100.

As can be seen from FIG. 1, this procedure can be used to detect pastchemical exposure status. The procedure could also be used to determinecauses for allergic reactions or auto-immunity responses. In some cases,the procedure could provide an output for therapeutic targets ofunwanted immune response (e.g., tolerance). Example embodiments may alsobe used by the intelligence community to determine exposure status forindividuals or populations. In some cases, routine monitoring ofindividuals (e.g., service members, healthcare workers, specialoperations forces, etc.) may indicate populations that are sensitized toa set of chemicals that could limit their deployability or involvementin certain missions.

In some cases, the procedure could be adapted to determine a level ofcirculating antibody specific to a chemical composition as a function oflevel, duration, chronicity and/or last event of exposure. In thisregard, for example, the libraries may further include information torelate particular level measurements, combinations of indicator levels,or patterns of decay of level measurements for a series of testsperformed over a period of time, correlate to an indication of an amountof exposure, a time since exposure, a duration of exposure, or how manyexposure incidents have occurred for a particular individual. Thisinformation may be derived, for example, based on statistical analysisof patient data for larger sets of historical data.

FIG. 2 illustrates an apparatus 200 for determining past exposure tochemical agents or heavy metals. The apparatus 200 may be a multiplexdetector since it is configured to enable exposure testing to beconducted for a plurality of different chemical agents and/or heavymetals. The detector may include a plurality of test volumes or cells210 inside which a mixture 220 can be formed including a capture reagentand a clinical sample. Each cell 210 may have a different capturereagent provided therein. Moreover, the capture reagent may be coated orotherwise provided on a capture material (e.g., a capture bead or otherstructure). The capture reagent may be selected based on an ability ofthe capture reagent to bind with a target antibody. The target antibodymay therefore act as an indicator associated with a particular chemicalagent or heavy metal.

As discussed above, in the case of chemical agents, the target antibodymay attach to protein adducts formed when exposure to the chemical agentoccurs in vivo. For heavy metals, the target antibody may attach tomodified biomolecules that were modified by exposure to heavy metals. Inany case, a phage library, DNA library, or modification library may beused to define a plurality of known modifications or protein adductsthat form based on exposure (in vivo) to corresponding heavy metals orchemical agents, respectively. Thus, each cell 210 may be provided witha different capture material to bind with antibodies (if any arepresent) that would be expected to form if exposure to the correspondingheavy metal or chemical agent has occurred.

After the clinical sample is mixed with the capture reagent, the mixturemay be incubated. Thereafter, unbound reagent may be removed by washingwith a suitable solution. After unbound reagent has been removed,specific binding events that have occurred can be determined. Of course,these binding events are indicative of the antibodies that were presentin the clinical sample, and therefore indicative of exposure to thecorresponding heavy metals or chemical agents defined in thecorresponding library. In an example embodiment, a PCR assay may beperformed to amplify the results and provide a clearer indication of thebinding events that occurred. Thereafter, in some cases, it may bedesirable to determine assay sensitivity and specificity for eachanalog.

Results of the determinations of binding events may be provided in amultiplex detection format (e.g., format 180) that shows informationabout which cells 210 (if any) had positive indications of exposureevents. In some cases, the detection format may further provideinformation about levels detected (i.e., the amount of antibody capturedfor the corresponding chemical-of interest or metal-of-interest).Whether the results merely show binary results (i.e., positive ornegative results for past exposure to the chemical-of interest ormetal-of-interest) or actually provide information indicative of a levelor degree of antibody capture events, the results may be displayed inreal time, or may be stored for future analysis.

FIG. 3 illustrates a block diagram of a method of determining pastexposure to chemical agents or heavy metals in accordance with anexample embodiment. The method may include coating a capture materialwith a capture reagent at operation 300. The capture reagent may beselected based on an ability of the capture reagent to bind with atarget antibody, and the target antibody may be an indicator associatedwith a particular chemical agent or heavy metal. The method may furtherinclude interrogating a clinical sample associated with an individual byforming a mixture of the capture material and the clinical sample atoperation 310, and determining an exposure status of the individual tothe particular chemical agent or heavy metal based on whether thecapture material demonstrates capture of the indicator at operation 320.

In cases where multiplexing is desired, the capture material in eachcell may be coated with a respective different capture reagents. Each ofthe different capture reagents may be known (e.g., via the libraries) tobind with corresponding different target antibodies to act as respectiveindicators of exposure to the chemical agents or heavy metals. In anexample embodiment, the capture material that is coated with the capturereagent may target bindings identified from a phage library, a DNAlibrary, or a modification library to determine the chemical agents orheavy metals that form corresponding protein adducts or biomoleculesmodifications to which each of the different target antibodies bind.

In an example embodiment, a determination regarding the exposure statusof the individual may be made by washing the mixture to remove unboundreagents. Thereafter, a determination may be made as to the bindingevents that have occurred in association with capture of the indicators.In some cases, a PCR assay may be performed to enhance the sensitivityof the exposure tests.

In some cases, the method may further include additional (optional)operations. For example, the method may further include storing theexposure status in association with the individual and a first test dateat operation 330, and performing the coating, interrogating anddetermining operations again at second test date to determine a changein exposure status and a timeframe for the change in exposure status atoperation 330. The operations 300 to 320 may be repeated again and againat various intervals to provide a timeline that may indicate exposureevent information for an individual over time. The timeline may enabledeterminations of when exposure events occur for the individual and, insome cases, whether chronic exposure, multiple discrete exposure events,a single exposure event, magnitude of exposure. In this regard, forexample, the first test date may form a baseline measurement in terms ofidentifying any chemical agents or heavy metals to which the individualhas been exposed. An indication of magnitude of the exposure may also beprovided by level measurements associated with the first test date.

The first test date may also, by negation, establish a number of testedchemical agents and heavy metals to which the individual has apparentlynot been exposed as of the first test date. Accordingly, if exposureoccurs after the first test date, the exposure may appear on asubsequent test date (e.g., the second test date) to establish a daterange within which the exposure must have occurred. The date range may,for example, correspond to a suspected exposure event, which may beconfirmed using testing methods associated with example embodiments.

When level measurement is possible and employed, levels measured at thefirst test date or at any subsequent test dates may be expected todecrease over time for certain chemicals or metals of interest. However,if levels measured increase slowly or in prompt jumps, other informationregarding the frequency or nature of exposure can be determined. Forexample, if levels slowly increase, such a pattern may be indicative ofa chronic (perhaps low level) exposure. Meanwhile, if levels weredecreasing, increase in one subsequent test, and then return todecreasing thereafter, the pattern may indicate a past exposure event,and a single subsequent exposure event. Other patterns may indicateother information, which may be determinable by studying temporal and/orlevel information associated with exposure analysis in accordance withexample embodiments.

Where baseline measurements and/or periodic measurements are availablefor comparison, definitive determinations regarding date ranges forexposure events can be established. However, even where baselinemeasurements were not made, a definitive determination regarding theoccurrence of a past exposure (regardless of when) can still be madeusing example embodiments. Exposure statuses for military or civiliansthat were potentially targets of chemical weapons can therefore bedetermined over a range of possible agents, and within any suitable orpracticable time period after a potential exposure event.

In some cases, as suggested above, it may be possible to determine someinformation about the type or nature of an exposure event or patternbased on test results. For example, level measurements coupled withinformation about the time since an exposure event may provide anindication of the magnitude of exposure. In some cases, the librariesmay further include information indicative of level decay rates forvarious agents or metals, so that estimates can be generated based onavailable information regarding level and time for each individual agentor metal for which an exposure event is detected.

Thus, in some example embodiments, temporal information and/or type ofexposure can be determined based on a regimen of testing. Moreover,given temporal information and level measurements, other informationabout the type of exposure and/or patterns of exposure may also bedeterminable. Example embodiments may therefore enable multiplexexposure detection to be accomplished for various metal ions (e.g.,heavy metals) and chemical agents. Example embodiments may also beextended to provide further insights into autoimmune diseases andenvironmental exposures to improve public health and responses tohumanitarian crises.

FIG. 4 illustrates a block diagram showing operations associated with amethod for identifying possible host biomolecule modifications thatillicit immune response following an exposure event to a chemical agentor heavy metal. As shown in FIG. 4, the method may include incubating ahost phage/yeast peptidome library or oligo-tag peptidome library with achemical of interest or heavy metal to generate all possible adducts orbiomolecule conformational alterations at operation 400. The method mayfurther include interrogating serum samples from a known exposedindividual with the aforementioned reagents at operation 410.Thereafter, the method may include coupling immunoassay and DNAsequencing to identify specific host biomolecule modifications that werehaptenized to illicit immune response at operation 420. An additional,optional modification to the method may include providing capturereagents as peptide and/or biomolecule arrays that are capable to bindto circulating antibodies that were generated by exposure to thechemical of interest or heavy metal at operation 430. Thus, as a resultof the method of FIG. 4. Sufficient information may be determined toengage in the method of FIG. 3 with the corresponding identified capturereagents.

Many modifications and other embodiments of the inventions set forthherein will come to mind to one skilled in the art to which theseinventions pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Moreover, although the foregoing descriptions and the associateddrawings describe exemplary embodiments in the context of certainexemplary combinations of elements and/or functions, it should beappreciated that different combinations of elements and/or functions maybe provided by alternative embodiments without departing from the scopeof the appended claims. In this regard, for example, differentcombinations of elements and/or functions than those explicitlydescribed above are also contemplated as may be set forth in some of theappended claims. In cases where advantages, benefits or solutions toproblems are described herein, it should be appreciated that suchadvantages, benefits and/or solutions may be applicable to some exampleembodiments, but not necessarily all example embodiments. Thus, anyadvantages, benefits or solutions described herein should not be thoughtof as being critical, required or essential to all embodiments or tothat which is claimed herein. Although specific terms are employedherein, they are used in a generic and descriptive sense only and notfor purposes of limitation.

What is claimed is:
 1. An apparatus for determining past exposure tochemical agents or heavy metals, the apparatus comprising: a firstcapture material coated with a first capture reagent, the first capturereagent configured to bind to a first target antibody; wherein the firsttarget antibody is an indicator associated with a first modifiedbiomolecule associated with exposure to a first heavy metal, wherein thefirst heavy metal is lead; a second capture material coated with asecond capture reagent, the second capture reagent configured to bind toa second target antibody; wherein the second target antibody is anindicator associated with a second modified biomolecule associated withexposure to a second heavy metal; a clinical sample associated with anindividual; a plurality of test cells including a first test cellhousing a first mixture of the first capture material and the clinicalsample, and a second test cell housing a second mixture of the secondcapture material and the clinical sample; and a detector configured toindicate (i) whether the first capture material formed a bond with thefirst target antibody and (ii) whether the second capture materialformed a bond with the second target antibody.
 2. The apparatus of claim1, further comprising a third capture material coated with a thirdcapture reagent, the third capture reagent configured to bind to a firstprotein adduct; wherein the first protein adduct is an indicatorassociated with exposure to a first chemical agent; the plurality oftest cells further comprising a third test cell housing a third mixtureof the third capture material and the clinical sample; and the detectoris further configured to indicate whether the third capture materialformed a bond with the first protein adduct.
 3. The apparatus of claim2, further comprising a fourth capture material coated with a fourthcapture reagent, the fourth capture reagent configured to bind to asecond protein adduct; wherein the second protein adduct is an indicatorassociated with exposure to a second chemical agent; the plurality oftest cells further comprising a fourth test cell housing a fourthmixture of the fourth capture material and the clinical sample; and thedetector is further configured to indicate whether the fourth capturematerial formed a bond with the second protein adduct.
 4. An apparatusfor determining past exposure to chemical agents or heavy metals, theapparatus comprising: a first plurality of capture materials coated witha first plurality of respective capture reagents, the first plurality ofcapture materials being configured to bind to a first plurality ofrespective target antibodies; wherein the first plurality of respectivetarget antibodies is an indicator associated with a first plurality ofrespective modified biomolecules associated with exposure to a firstheavy metal, wherein the first heavy metal is lead; a second pluralityof capture materials coated with a second plurality of respectivecapture reagents, the second plurality of capture materials beingconfigured to bind to a second plurality of respective targetantibodies; wherein the second plurality of respective target antibodiesis an indicator associated with a second plurality of respectivemodified biomolecules associated with exposure to a second heavy metal;a clinical sample associated with an individual; a first plurality oftest cells housing a first plurality of respective mixtures of the firstplurality of respective capture materials and the clinical sample; asecond plurality of test cells housing a second plurality of respectivemixtures of the second plurality of respective capture materials and theclinical sample; and a detector configured to indicate whether anybinding reactions occurred between (i) any of the first plurality ofrespective capture materials and the first plurality of respectivetarget antibodies, and (ii) any of the second plurality of respectivecapture materials and the second plurality of respective targetantibodies.
 5. An apparatus for determining past exposure to chemicalagents or heavy metals, the apparatus comprising: a first capturematerial coated with a first capture reagent, the first capture reagentconfigured to bind to a first protein adduct; wherein the first proteinadduct is an indicator associated with exposure to a first chemicalagent; a clinical sample associated with an individual; at least onetest cells housing a mixture of the first capture material and theclinical sample; and a detector configured to indicate whether the firstcapture material formed a bond with the first protein adduct.
 6. Theapparatus of claim 5, further comprising a second capture materialcoated with a second capture reagent, the second capture reagentconfigured to bind to a second protein adduct; wherein the secondprotein adduct is an indicator associated with exposure to a secondchemical agent; the at least one test cells comprises a plurality oftest cells including a first test cell housing a first mixture of thefirst capture material and the clinical sample, and a second test cellhousing a second mixture of the second capture material and the clinicalsample; and the detector is further configured to indicate whether thesecond capture material formed a bond with the second protein adduct. 7.The apparatus of claim 5, wherein the first chemical agent is sarin gas.8. The apparatus of claim 5, wherein the first chemical agent is mustardgas.
 9. The apparatus of claim 6, wherein the first chemical agent issarin gas and the second chemical agent is mustard gas.